In a method for manufacturing a semiconductor device, an insulating film is formed on a front surface (the surface on which a semiconductor element to be formed) of a semiconductor wafer. However, when the insulating film is formed on the semiconductor wafer using, for example, a chemical vapor deposition (CVD) method and a thermal oxidation method, the insulating film is formed on both surfaces of the front and back (an opposite side to the front surface) of the semiconductor wafer. When removing the insulating films formed on the surfaces of the semiconductor wafer as described above, the insulating films formed on the front and back surfaces of the semiconductor wafer are simultaneously removed by wet etching in batch processing.
In Japanese Patent Application Publication No. JP-A-2003-59931, in order to remove dust and foreign objects adhered on a back surface of a semiconductor wafer, a technique to selectively spray purified water onto the back surface of the semiconductor wafer and then to chemically treat the semiconductor wafer in batch processing has been disclosed. In Japanese Patent Application Publication No. JP-A-2004-356593, in order to remove particles adhered on a thin film which is formed on a back surface of a semiconductor wafer, a technique to partially etch the thin film on the back surface has been disclosed.